Hydrangea plant named ‘HI HORIZON’

ABSTRACT

A new and distinct cultivar of  Hydrangea  plant named ‘HI HORIZON’, characterized by its upright and broadly spreading plant habit; moderately vigorous and moderate growth rate; freely branching habit; strong and sturdy stems; freely flowering habit; large and dense inflorescences with purplish red-colored sterile flowers; and good post-production longevity.

Botanical designation: Hydrangea macrophylla.

Cultivar denomination: ‘HI HORIZON’.

STATEMENT REGARDING PRIOR DISCLOSURES BY INVENTOR/APPLICANT & ASSIGNEE

A Japanese Plant Breeder's Rights application for the instant plant was filed by the Applicant/Assignee of the instant application, Hi Breeding B.V. of De Lier, The Netherlands on Jun. 26, 2020, application number 34797. Foreign priority is not claimed to this Japanese Plant Breeder's Rights application.

The Inventor/Applicant and Assignee assert that no publications nor advertisements relating to sales, offers for sale or public distribution occurred more than one year prior to the effective filing date of this application. Any information about the claimed plant would have been obtained from a direct or indirect disclosure from the Inventor/Applicant and/or the Assignee. Inventor/Applicant and Assignee claim a prior art exception under 35 U.S.C. 102(b)(1) for disclosure and/or sales prior to the filing date but less than one year prior to the effective filing date.

BACKGROUND OF THE INVENTION

The present invention relates to a new and distinct cultivar of Hydrangea plant, botanically known as Hydrangea macrophylla, commercially referred to as a mophead-type Hydrangea and hereinafter referred to by the name ‘HI HORIZON’.

The new Hydrangea plant is a product of a planned breeding program conducted by the Inventor in De Lier, The Netherlands. The objective of the breeding program is to create new sturdy and strong Hydrangea plants with attractive inflorescences and good postproduction longevity.

The new Hydrangea plant originated from a cross-pollination on Apr. 14, 2015 of a proprietary selection of Hydrangea macrophylla identified as code number 1560, not patented, as the female, or seed, parent with a proprietary selection of Hydrangea macrophylla identified as code number 1562, not patented, as the male, or pollen, parent. The new Hydrangea plant was discovered and selected as a single flowering plant from within the progeny of the stated cross-pollination in a controlled greenhouse environment in De Lier, The Netherlands on Apr. 4, 2017.

Asexual reproduction of the new Hydrangea plant by terminal vegetative cuttings since Jun. 11, 2017 in a controlled greenhouse environment in De Lier, The Netherlands has shown that the unique features of this new Hydrangea plant are stable and reproduced true to type in successive generations of asexual reproduction.

SUMMARY OF THE INVENTION

Plants of the new Hydrangea have not been observed under all possible combinations of environmental conditions and cultural practices. The phenotype may vary somewhat with variations in environmental conditions such as temperature and light intensity without, however, any variance in genotype.

The following traits have been repeatedly observed and are determined to be the unique characteristics of ‘HI HORIZON’. These characteristics in combination distinguish ‘HI HORIZON’ as a new and distinct Hydrangea plant:

-   -   1. Upright and broadly spreading plant habit.     -   2. Moderately vigorous and moderate growth rate.     -   3. Freely branching habit.     -   4. Strong and sturdy stems.     -   5. Freely flowering habit.     -   6. Large and dense inflorescences with purplish red-colored         sterile flowers.     -   7. Good post-production longevity.

Plants of the new Hydrangea can be compared to plants of the female parent selection. Plants of the new Hydrangea differ primarily from plants of the female parent selection in the following characteristics:

-   -   1. Plants of the new Hydrangea are not as vigorous as plants of         the female parent selection.     -   2. Stems of plants of the new Hydrangea are sturdier than stems         of plants of the female parent selection.     -   3. Plants of the new Hydrangea are tolerant to Botrytis whereas         plants of the female parent selection are very susceptible to         Botrytis.

Plants of the new Hydrangea can be compared to plants of the male parent selection. Plants of the new Hydrangea differ primarily from plants of the male parent selection in the following characteristics:

-   -   1. Stems of plants of the new Hydrangea are sturdier than stems         of plants of the male parent selection.     -   2. Sterile flowers of plants of the new Hydrangea are firmer         than sterile flowers of plants of the male parent selection.

Plants of the new Hydrangea can also be compared to plants of Hydrangea macrophylla ‘HBA 202911’, not patented. In side-by-side comparisons, plants of the new Hydrangea differ primarily from plants of ‘HBA 202911’ in the following characteristics:

-   -   1. Stems of plants of the new Hydrangea are sturdier than stems         of plants of ‘HBA 202911’.     -   2. Sterile flowers of plants of the new Hydrangea are firmer         than sterile flowers of plants of ‘HBA 202911’.

BRIEF DESCRIPTION OF THE PHOTOGRAPHS

The accompanying colored photographs illustrate the unique appearance of the new Hydrangea plant showing the colors as true as it is reasonably possible to obtain in colored reproductions of this type. Colors in the photographs may differ from the color values cited in the detailed botanical description which accurately describe the colors of the new Hydrangea plant.

The photograph on the first sheet (FIG. 1 ) is a side perspective view of a typical flowering plant of ‘HI HORIZON’ grown in a container.

The photograph at the top of the second sheet (FIG. 2 ) is a close-up view of a typical inflorescence of ‘HI HORIZON’.

The photograph at the bottom of the second sheet (FIG. 3 ) is a close-up view of a typical leaf of ‘HI HORIZON’.

The photograph on the third sheet (FIG. 4 ) is a top perspective view of a typical flowering plant of ‘HI HORIZON’ that has been treated with aluminum sulfate, or “blued”.

DETAILED BOTANICAL DESCRIPTION

Plants used in the aforementioned photographs and in the following description were grown during the late autumn and early winter in 14-cm containers in a glass-covered greenhouse in De Lier, The Netherlands and under cultural practices typical of commercial Hydrangea production. During the production of the plants, day temperatures ranged from 20° C. to 35° C., night temperatures ranged from 10° C. to 22° C. and light levels averaged 4,000 lux. Plants of the new Hydrangea were pinched one time and were 18 months old when the photographs and description were taken. In the following description, color references are made to The Royal Horticultural Society Colour Chart, 2015 Edition, except where general terms of ordinary dictionary significance are used.

-   Botanical description: Hydrangea macrophylla ‘HI HORIZON’. -   Parentage:     -   -   Female, or seed, patent.—Proprietary selection of Hydrangea             macrophylla identified as code number 1560, not patented.         -   Male, or pollen, patent.—Proprietary selection of Hydrangea             macrophylla identified as code number 1562, not patented. -   Propagation:     -   -   Type cutting.—By vegetative terminal cuttings.         -   Time to initiate roots, summer.—About twelve days at             temperatures about 22° C.         -   Time to initiate roots, winter.—About two weeks at             temperatures about 20° C.         -   Time to produce a rooted young plant, summer.—About four             weeks at temperatures about 22° C.         -   Time to produce a rooted young plant, winter.—About one             month at temperatures about 19° C.         -   Root description.—Medium in thickness, fibrous; typically             white in color, actual color of the roots is dependent on             substrate composition, water quality, fertilizer type and             formulation, substrate temperature and physiological age of             roots.         -   Rooting habit.—Moderately freely branching; medium density. -   Plant description:     -   -   Plant and growth habit.—Upright and broadly spreading plant             habit; flattened globular in overall shape; strong and             sturdy stems; moderately vigorous growth habit and moderate             growth rate; about six months from propagation are required             to produce small finished flowering plants.         -   Plant height.—About 26.6 cm.         -   Plant diameter or area of spread.—About 46.5 cm. -   Lateral branch description:     -   -   Branching habit.—Freely branching habit with about eight             lateral branches per plant; pinching enhances lateral branch             development.         -   Length.—About 13.8 cm.         -   Diameter.—About 6 mm.         -   Internode length.—About 3.8 cm.         -   Strength.—Strong, sturdy.         -   Aspect.—About 50° from vertical.         -   Texture, developing and fully developed.—Smooth, glabrous;             becoming woody with subsequent development.         -   Color, developing.—Close to 146D.         -   Color, fully developed.—Close to between 143B to 143C and             146C; when woody, close to N199B and 200D.         -   Lenticels.—Density: Sparse to medium density. Length: About             1.5 mm. Diameter: About 0.5 mm. Color: Close to 182A to             182B. -   Leaf description:     -   -   Arrangement.—Opposite, simple.         -   Length.—About 11.1 cm.         -   Width.—About 7.5 cm.         -   Shape.—Broadly ovate to broadly elliptic.         -   Apex.—Apiculate.         -   Base.—Short attenuate.         -   Margin.—Serrate to crenate-serrate.         -   Texture, upper surface.—Slightly rugose, glabrous.         -   Texture, lower surface.—Moderately rugose, glabrous.         -   Venation pattern.—Pinnate.         -   Color.—Developing leaves, upper surface: Close to between             137C and 143A. Developing leaves, lower surface: Close to             between 138A and 147B. Fully developed leaves, upper             surface: Close to between NN137A and 147A; venation, close             to 146D. Fully developed leaves, lower surface: Close to             137C; venation, close to 147D.         -   Petioles.—Length: About 3.3 cm. Diameter: About 3 mm to             4 mm. Texture and luster, upper and lower surfaces: Smooth,             glabrous; moderately glossy. Color, upper surface: Close to             144A. Color, lower surface: Close to between 144A and 146D. -   Flower description:     -   -   Flower type and habit.—Showy rotate sterile flowers and             small, inconspicuous rotate fertile flowers arranged on             mophead-type terminal panicles; panicles flattened globular             in shape; sterile flowers face upright to outwardly and             fertile flowers mostly upright.         -   Fragrance.—None detected.         -   Natural flowering season.—In the garden, plants flower             continuously from the late spring to late summer in The             Netherlands; flower dormancy can be broken with a cold             storage treatment.         -   Flower longevity.—Good postproduction longevity; sterile             flowers maintain good substance for about six weeks on the             plant, sterile flowers persistent; fertile flowers last for             a few days on the plant, fertile flowers not persistent.         -   Quantity of flowers.—Freely flowering habit; about 250             sterile flowers per panicle and about 70 fertile flowers per             panicle.         -   Panicle height.—About 9.3 cm.         -   Panicle diameter.—About 15.2 cm.         -   Panicle peduncles.—Length: About 5.8 cm. Diameter: About             3.5 mm. Strength: Strong. Aspect: Primary peduncles, mostly             erect; lateral peduncles, about 40° from primary peduncle             axis. Texture: Densely pubescent. Color: Close to 145C to             145D; at the nodes, slightly tinged with close to 183D.         -   Sterile flower buds.—Length: About 7 mm. Diameter: About             1.2 cm. Shape: Irregular and broadly cup-shaped. Color:             Close to 70C.         -   Fertile flower buds.—Length: About 5 mm. Diameter: About             5 mm. Shape: Globular. Color: Close to 63B.         -   Sterile flower diameter.—About 2.2 cm to 4.6 cm.         -   Sterile flower depth (height).—About 0.8 cm to 2.2 cm.         -   Fertile flower diameter.—About 9 mm.         -   Fertile flower depth (height).—About 6 mm.         -   Petals, sterile flowers.—Quantity and arrangement: Four in a             single whorl. Length: About 4 mm. Width: About 2.25 mm.             Shape: Broadly ovate, concave. Apex: Acute. Base: Cuneate.             Margin: Entire. Texture and luster, upper and lower             surfaces: Smooth, glabrous; matte. Color: When opening and             fully opened, upper surface: Close to N66C and N66D; towards             the margins, close to 75D; towards the base, close to N155A;             color does not change with subsequent development. When             opening and fully opened, lower surface: Close to 78B;             towards the margins, close to 75D; towards the base, close             to N155A; color does not change with subsequent development.         -   Petals, fertile flowers.—Quantity and arrangement: Five in a             single whorl. Length: About 4 mm. Width: About 2.25 mm.             Shape: Ovate, concave. Apex: Acute. Base: Cuneate. Margin:             Entire. Texture and luster, upper and lower surfaces:             Smooth, glabrous; matte. Color: When opening and fully             opened, upper surface: Close to N66C and N66D; towards the             margins, close to 75D; towards the base, close to N155A;             color does not change with subsequent development. When             opening and fully opened, lower surface: Close to 78B;             towards the margins, close to 75D; towards the base, close             to N155A; color does not change with subsequent development.         -   Sepals, sterile flowers.—Quantity and arrangement: Typically             four, or occasionally five, in a single whorl. Length: About             1.7 cm. Width: About 2.2 cm. Shape: Reniform. Apex:             Shallowly retuse to rounded. Base: Truncate to short             acuminate. Margin: Entire; coarsely undulate. Texture and             luster, upper and lower surfaces: Smooth, glabrous; matte.             Color: When opening, upper surface: Close to 63B. When             opening, lower surface: Close to 64D. Fully opened, upper             surface: Close to 63B and 63C; with subsequent development,             color becoming closer to N66D; when treated with aluminum             sulfate or “blued”, color becoming closer to 96B. Fully             opened, lower surface: Close to 64D; with subsequent             development, color becoming closer to 63 C; when treated             with aluminum sulfate or “blued”, color becoming closer to             96C.         -   Sepals, fertile flowers.—Quantity and arrangement: Five in a             single whorl. Length: About 1.75 mm. Width: About 1.25 mm.             Shape: Broadly ovate. Apex: Broadly acute. Base: Broadly             cuneate. Margin: Entire. Texture and luster, upper and lower             surfaces: Smooth, glabrous; matte. Color: When opening and             fully opened, upper surface: Close to 63C; color does not             change with subsequent development. When opening and fully             opened, lower surface: Close to 65A; color does not change             with subsequent development.         -   Pedicels, sterile flowers.—Length: About 1.8 cm. Diameter:             About 1.5 mm. Strength: Moderately strong. Aspect: About 30°             from main peduncle axis Texture and luster: Moderately             pubescent; matte. Color: Close to 63A.         -   Pedicels, fertile flowers.—Length: About 7 mm. Diameter:             About 1 mm. Strength: Moderately strong. Aspect: About 10°             from vertical. Texture and luster: Moderately pubescent;             matte. Color: Close to 63C to 63D.         -   Reproductive organs, sterile flowers.—Stamens: Quantity per             flower: Eight. Filament length: About 3 mm. Filament color:             Close to 69C. Anther shape: Broadly oblong. Anther length:             About 1 mm. Anther color: Close to 155A. Pollen amount:             Moderate. Pollen color: Close to 156D. Pistils: Pistil             quantity per flower: Two or three. Pistil length: About             1.5 mm. Stigma shape: Club-shaped. Stigma color: Close to             75C. Style length: About 1 mm. Style color: Close to 73C.             Ovary color: Close to 69D.         -   Reproductive organs, fertile flowers.—Stamens: Quantity per             flower: Eight. Filament length: About 3 mm. Filament color:             Close to 69C. Anther shape: Broadly oblong. Anther length:             About 1 mm. Anther color: Close to 155A. Pollen amount:             Moderate. Pollen color: Close to 156D. Pistils: Pistil             quantity per flower: Three. Pistil length: About 1.5 mm.             Stigma shape: Club-shaped. Stigma color: Close to 75C. Style             length: About 1 mm. Style color: Close to 73C. Ovary color:             Close to 150D.         -   Seeds.—To date, seed development has not been observed on             plants of the new Hydrangea. -   Pathogen & pest resistance: Plants of the new Hydrangea have been     observed to be tolerant to Botrytis (Botrytis cinerea). To date,     plants of the new Hydrangea have not been observed to be resistant     to pests and other pathogens common to Hydrangea plants. -   Temperature tolerance: Plants of the new Hydrangea have been shown     to be suitable for USDA Hardiness Zones 5 through 9. 

It is claimed:
 1. A new and distinct Hydrangea plant named ‘HI HORIZON’ as illustrated and described. 